<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Visualize population density</title>
    <meta
      name="viewport"
      content="initial-scale=1,maximum-scale=1,user-scalable=no"
    />
    <script src="../../lib/mapbox-gl.js"></script>
    <link href="../../lib/mapbox-gl.css" rel="stylesheet" />
    <script src="../../lib/axios.min.js"></script>
    <style>
      body {
        margin: 0;
        padding: 0;
      }
      #map {
        position: absolute;
        top: 0;
        bottom: 0;
        width: 100%;
      }
    </style>
  </head>
  <body>
    <div id="map"></div>
    <script>
      let baseDataUrl = `http://${localStorage.getItem(
        "host"
      )}/mapbox-gl-js-offline-examples`;
      axios
        .get(
          baseDataUrl +
            `/resources/styles/${localStorage.getItem(
              "mbtilesStylesName"
            )}.json`
        )
        .then((res) => {
          let data = res.data;
          initMap(data);
        })
        .catch((err) => {
          console.error(err);
        });

      function initMap(style) {
        let map = new mapboxgl.Map({
          container: "map",
          center: [30.0222, -1.9596], // starting position [lng, lat]
          zoom: 7, // starting zoom
          style: style,
        });

        map.on("load", function () {
          map.addSource("rwanda-provinces", {
            type: "geojson",
            data: baseDataUrl + "/data/geojson/rwanda-provinces.geojson",
          });
          map.addLayer({
            id: "rwanda-provinces",
            type: "fill",
            source: "rwanda-provinces",
            layout: {},
            paint: {
              "fill-color": [
                "let",
                "density",
                ["/", ["get", "population"], ["get", "sq-km"]],
                [
                  "interpolate",
                  ["linear"],
                  ["zoom"],
                  8,
                  [
                    "interpolate",
                    ["linear"],
                    ["var", "density"],
                    274,
                    ["to-color", "#edf8e9"],
                    1551,
                    ["to-color", "#006d2c"],
                  ],
                  10,
                  [
                    "interpolate",
                    ["linear"],
                    ["var", "density"],
                    274,
                    ["to-color", "#eff3ff"],
                    1551,
                    ["to-color", "#08519c"],
                  ],
                ],
              ],
              "fill-opacity": 0.7,
            },
          });
        });
      }
    </script>
  </body>
</html>
